The invention concerns a device for sintering differing molded parts in particular from foaming plastic in a form tool that is appropriate for each, that communicates with a device that can be controlled and that supplies media like foaming plastic, steam, cold water, vacuum, and compressed air as needed, that has at least one pressure transducer and/or temperature transducer mounted on its mold wall and connected on its input side to controls that constantly compare the actual pressure and temperature with an associated given value and release appropriate control signals to the supply device depending on the results of the comparison and on given time values.
Simultaneously manufacturing differing molded parts in devices of the aforesaid type in accordance with the various shapes that are separately inserted in a device is known. The foaming material is supplied from a central supply device to the tool's injectors and the supply of heating, sintering, and cooling media and of the pressure medium that opens and closes the mold is controlled in accordance with time data and the comparison of pressures or of heating and/or cooling temperatures with reference values obtained by tests conducted by the controls by appropriately opening and closing valves in the supply device.
The reference temperatures for heating or cooling the wall of the mold and the level of pressure that determines the sintering time are always valid for only a specific starting material. When there is a transition to another starting material, which is necessary at various times in practice, it is necessary in order to optimize the time intervals and energy consumption to decrease step by step, beginning with excessively long times during further operating cycles, down to minimum times that can be obtained with an economically reasonable expenditure of energy and to do so while retaining relationships in which sintering and cooling will be adequate. These series of tests have proved to be very expensive.
The method is also limited by the capacity for processing only one type of starting material at one time in the various molds because, although timing control based on comparisons of pressure and temperature can indeed deal with the various shapes of the molds employed at one time in the device, it cannot take various materials into account.